Floor sander



April 25, 1933- H, w. I UNDQUls-r 1,905,296

FLOOR SANDER Filed July 26, 1929 2 Sheets-Sheet l I N I/ E N TOR#EMDR/eff il( aww/sr A TTORNE Y April 25, 1933- H. w. LUNDQUIST1,905,296

FLOOR SANDER Filed July 26, 1929 2 sheets-Sheet 2 1N VENTO/e HENDR/c/fIL/ La/vDQz//sr ATTORNEY Patented Apr. 25, 1933 UNrrED STATES PATENT"oFFl CE y FLOORv SANDER;

Application me@ s111526,

VMy invention relates to-fsanding machines and more particularly toportable machines for sanding oors of buildings.

The objects of my present invention are:

5 first, to provide a floor sander in which the chatter, usually presentin other sanders and causing the sanding drum to jump up and down whileusing the same, is reduced toY a minimum thereby ,causing smoothoperation l@ of the machine over the Hoor, reducing the time of making asmooth fiat finished surface Von the floor and substantially eliminatingfurrows, waves, or grooves inthe finished iioor; second, to provide amachine of 15 this class in which the driving mechanism is so arrangedthat the belts or chains will not be slackenedas the sanding drumis'raised or lowered from the iloorand also a machine of Y this class inwhich all of the chains or belts 2G can be readily tightened if and whendesired; third, to provide an attachment for sanding machines of thisclass whereby the above mentioned features may be applied to sandingmachines now in use and whereby the above named disadvantages may beeliminated therein; fourth, to provide a novel dust pan arrangement inconnection with a sander of this class whereby the greater portion ofthe dust may bedirected into the pan and whereby the pan may be raisedand lowered with the sanding drum; fifth, to provide a novel hoodarrangement for a sander of this class whereby the hood may be readilyraised so that the sanding drum may be readily accessible at alltimes,-par ticularly for changing the sanding paper or other abrasivematerial on the drum; sixth, to provide a novelly constructed sandingdrum; and, seventh, to provide a machine of this class and attachmentstherefor which are simple and economical of construction, durable,efficient and which will not readily deteriorate or get out of order. y

.With theseand other objects in view, as D will appear hereinafter, myinvention conrsists of certain novel features of construction,combination and arrangement of parts and portions, as will behereinafter de-l scribed in detail and particularly set forth in theappended claims, reference being had i929. seriaino. 381,196.

to the accompanying drawings `and to the characters of referencethereonwhich form a part of this application in which:V

Figure l is a fragmentary top `view of my sanding machine in itspreferred form of 55 construction, certain parts being broken away to,facilitate the illustration; Fig. 2 is a fragmentary side elevationalView thereof; Fig. 3 is a fragmentary top view thereofon an enlargedscale and partly in section; 00 Fig. 4 is a topview ofthe dust hood ofmy* machine andthe supportingvmeans therefor; Fig. 5 is a fragmentarysectional viewv of my machine taken through 5 5 of Fig. Vl showingparticularly the stationary dust 55 pipe,-the dust hood, .and also thesupporting portion thereof lin relation to the frame; Fig. 6 isiafragmentary perspective view showing fragmentarily the supporting armsand shiftable dust pan andtheir supporting meanspand relation tothe mainframe and the inlet end of the dust conductor; Fig. 7 is afragmentarytransverse-'sectional view of the kdrum incorporating myinvention; Fig. 8 is a fragmentary side elevational view 75' of aslightly modified form of construction, showing a V-belt drive; and Fig.9 is a fragmentary front elevational view of the modified construction.Like characters of reference refer to similar parts and portionsthroughout the views of the drawings.

The machine is carried on a main frame 1 which is supported near itsforward portions and at its opposite sides by wheels 2 mounted 'onnon-rotatable axles secured Vto the frame 1 and at its rear end by acaster 3, and is directed from place to placel by an Iinclinedbackwardly extending handle 4 of suitable length. VOn this frame 1 issupported 'the sanding drum 5 which is positioned,v forwardly oftheframe and is driven by any suitable means, such as an electric motor 6mounted on and at 'the' upper side of lthe frame land adjustablevforwardly and back-l wardly thereon.

Heretofore in Sanders of the' class shown, the sanding drum wassupported on arms which were fpivotally mounted on bolts 7 between theaxis ofrevolution of the motor and `thus causing the furrows, grooves,or

waves-in the Hoor. In my construction, I have changed the constructionof the drum supporting armsv and .loweredltheir v.pivotal axes, and havesupported from the bolts 7 arms 8 which are in the form of bracketsdepending from said bolts. Through the lower ends of the armsv orbrackets 8 extend' a unitary shaft 9 which is adapted to reinforce thelower ends of the arms 8 relative to each other, vthe shaft beingnon-rotatably mounted at the lower ends of the arms 8 and retainedagainst rotation by screws 10. The lower ends of the arms 8 are alsoprevented from being shifted readily forwardly or backwardly by straps11 which extend with one end around the shaft 9 and with their rear endsover the axles of the supporting wheels 2, as shown in Figs. 2 and 3.

,On the shaft 9, immediately `outwardly from .the outer sides of thelower ends of the arms or brackets 8, are pivotally mounted theA drumsupporting arms 12, one at each Side of the frame, saidarms beingpivotally supported intermediate their ends. On these arms v12andintermediate their pivotal mounting and the forward side of such arms,is rotatablyV mounted the sanding drum 5, they same being mounted on aspindle 13 which extends through one of the drum supporting arms and isprovided at its outer end with a sprocket 14. This sprocketl/l is drivenby a chain 15 extending around a sprocket 16 mounted, together withanother sprocket 17, on the shaft9. It will be noted that the end of theshaft 9 on which Vthe sprockets 16 and 17 are mounted is reduced indiameter with its axisv eccentric to the main axis of the shaft 9. Thuswhen the set screw 10 is unloosened and the shaft 9.1-0- tated slightly,the tension on the chain 15 may be readily increased to take up forwearin the chain and sprocket. On the end of the shaft 9 opposite thereduced portion maybe provided a head9l to facilitate the turning of theshaft, as shown best in Fig.y 3.

n It will be here noted that the strap 11`on the side of the machine atwhich'the sprockets are located may be provided at the end connectedwith the shaft 9with'an eccentric bushing llt-keyed to the shaft 9 vsothat the axis of rotation of the shaft in saidfstrap is concentric with.the axis of rotation of the shaft in the arms or brackets 8. i

,The sprockets 16 and 17 arepreferably secured together as a unit, asshown in Fig. 3, and the sprocket 16 is driven by the sprocket 17 Thesprocket 17 is driven by a chain extending around the sprocket 19secured to the shaft of the motor 6. Thus it will be seen that the axesof rotation of the sprockets 16 and 17 are relatively lixed axes and anyplay or slap in the same will not be conducted in the form of chatter tothe sanding drum 5. The distance between the axes of the sprockets 14and 16, when the sanding drum is rotated, is always fixed, thuspreventing such alternate tightening and lengthening fand Vconsequentslapping in the chain as was customary in former types of machines ofthis class, thus further reducing chatter of the sanding drum. The drumis' raised and ylowered by the portions of thearms 12 extendingbackwardly from the pivotal axis, namely, the ,portions designated 12ain the drawings. The rearwardly extended ends ofthese portions areflexibly connected to arms 20 in any suitable manner for raising andlowering the sanding drum from and to the floor. On the machine isprovided a dust pipe 21 which terminates at its forward` end in adiverging mouth piece or dustV pan 22 whichris positioned near thefloorbehind the sanding drum 5. Dueto the fixed relation ofthe dust pipe 21and dust .pan 22 tothe frame and the more or less great distance fromthedrum 5, I have provided another dust pan 23v to fill the spacelbetween the dust pan 22 and the drum 5. Thisdust pan 23,1is of lightconstruction and is pivotally mounted near its rear edge at the forwardportion of the dust pan 22 and is pivotally connected near itsforwardedge, by a pair of links 24, at its opposite sides to the drumsupporting arms 12 immediately backwardly from the portions thereof onwhich the drum is rotatably mounted. Thus, when the drum is raised andlowered, the dust pan 23 is raisedand lowered therewith, permitting thedust pan 23 to be placed very close to the floor and very close to thesanding drum.

With my construction it is possible to increase the 4speed of thesanding drum fifty percent more than former machines of this class. Theincrease in speed causes a great deal of the dust to pass around withthc drum and upwardly. I have therefore provided a light hood 25 overand around the upper land front side of the drum, with the forwardportion extending downwardly as anjapron in front of the drumsubstantially to the floor, as designated by 25a in Fig. 2. Y This hood25 is pivoted at its lrear end on adust directing and supporting member26 which preferably extends from the dust panto the hood 25. This hoodmay bereadily raised out of the way of the drumso that the drum may bereadily accessible at all times for changing the sand paper or othersanding material.

Inmy machine I have provided a special drum, the body or outer portionof which may a split cylindrical metal member 5a. Immediately over theouter surface of this cylindrical metal member 5c I have secured a padof sponge rubber 11. To the outer side of the pad of sponge rubber 31 issecured a pad of readily yieldable sheet rubber 32. Over the outer sideof the pad of readily yieldable sheet rubber is removably positioned andsecured a sheet of sand paper or other sanding material Although asponge rubber has been used heretofore in machines of this class betweenthe rigid drum and the sand paper, the combination of readily yieldablesheet rubber and sponge rubber has not been used to my knowledge. Insanding floors, it often happens that the nails in the floor or otherobstructions on the oor are forced through the sand paper into thesponge rubber tearing both the sand paper and the sponge rubber. Butwithv the application of a readily yieldable sheet rubber on the outsideof the sponge rubber, the latter is protected from such obstructions.

In the structure shown in Figs. 8 and 9 of the drawings, in place of thesprockets 19 and 14, mounted respectively on the shaft of the motor 6and on the spindle 13, I have provided sheaves 41 and 42 which areprovided with peripheral V-shaped grooves, as shown best in Fig. 9.Around these sheaves extends a flexible belt 43 of V-shaped crosssection. On the reduced eccentric portion 9ct of the shaft 9 is an idlersheave 44 also having peripheral V-shaped grooves. The belt 43 extendsaround the lower side of the idler sheave 44, and when the motor shaftis rotated in the direction indicated by the arrow, the pull upon thesheave 42 is the same as that exerted by the chains in the constructiondescribed above. By reason of the use of the V-shaped belt, any raisingor lowering of the sander drum, which may cause loosening` or tighteningof the belt, will not affect the smooth running of the operatingmechanism, and the pull upon the sheave 42 will always be about thecenter of revolution of the sheave 44.

Though I have shown and described a particular construction, combinationafnd arrangement of parts and portions, and a certain modificationthereof, I do not wish to be limited to this particular construction,combination and arrangement, nor to the modication, but desire toinclude in the scope of my invention the construction, conibination andarrangement substantially as set forth in the appended claims.

I claim as new and desire to secure by Letters Patent is:

l. In an attachment of the class described for sanding machines, thecombination with a portable frame having supporting wheels, a sandingdrum, and a motor on the frame for driving said drum, of a pair of armspositioned at the opposite sides of the forward end of the frame andsecured at their upper ends thereto, a pair of drum supporting armspivotally mounted intermediate their ends at the lower ends at the outersides of said first arms, said drum being rotatably mounted on said drumsupporting arms forwardly of said frame, means at the rear ends of saiddrum supporting arms for supporting said drum vfrom and resiliently onthe floor, means operatively connecting said motor to said drum, andstraps rigidly connecting the lower endof the first arm to the pivotalaxes of the supporting wheels of the frame.

2. In an attachment of the class described for sanding machines, thecombination with a portable frame, a sanding drum, and a motor on theframe for driving said drum, of a pair ofarms positioned at the oppositesides of the forward end of the frame and secured at their upper endsthereto, a pair of drum supporting arms pivotally mounted intermediatetheir ends at the lower ends at the outer sides of said first arms, saiddrum being rotatably mounted on said drum supporting arms forwardly ofsaid frame, a second pair of arms connecting the pivotal mounting ofsaid drum supporting arms to said frame, a wheel member mounted on thepivotal mounting of said drum supporting arms, drive Imeans operativelyconnect- .ing said motor and said drum, said drive means passing overand in engagement with said wheel member.

3. In an attachment of the class described foi' sanding machines, thecombination with a portable frame, a sanding drum, and av motor, havinga pulley mounted thereon,

mounted on said frame and adapted to drive said drum, of a pair -of armspositioned at the opposite sides of the forward end of the frame andsecured at their upper ends thereto, a pair of drum supporting armspivotally mounted on said first arms, said drum being rotatably mountedon said drum supporting arms forwardly of said frame, a third pair ofarms connecting the pivotal mounting of said drum support-ing arms tosaid frame,a pulley mounted coaxial with said drum, a second pulleymounted coaxial with the pivotal portions of said drum supporting arms,and a belt extending around all of said pulleys for driving said drum.

In testimony whereof, lI have hereunto set my hand at Los Angeles,California, this 10th day of Julv 1929. Having thus described myinvention, what' HENDRICK w. LUNDQUisT.

